1. Field of the Invention
The invention is in the field of radio frequency identification (RFID) devices, and methods for making such devices.
2. Description of the Related Art
Radio frequency identification (RFID) tags and labels (collectively referred to herein as “devices”) are widely used to associate an object with an identification code or other information. RFID devices generally have a combination of antennas and analog and/or digital electronics, which may include for example communications electronics, data memory, and control logic. For example, RFID tags are used in conjunction with security locks in cars, for access control to buildings, and for tracking inventory and parcels.
As noted above, RFID devices are generally categorized as labels or tags. RFID labels are RFID devices that are adhesively or otherwise have a surface attached directly to objects. RFID tags are secured to objects by other means, for example by use of a plastic fastener, string, or other fastening means.
RFID devices include active tags and labels, which include a power source, and passive tags and labels, which do not. In the case of passive devices, in order to retrieve the information from the chip, a “base station” or “reader” sends an excitation signal to the RFID tag or label. The excitation signal energizes the tag or label, and the RFID circuitry transmits the stored information back to the reader. The RFID reader receives and decodes the information from the RFID tag. In general, RFID devices can retain and transmit enough information to uniquely identify individuals, packages, inventory and the like. RFID tags and labels also can be characterized as to those to which information is written only once (although the information may be read repeatedly), and those to which information may be written during use. For example, RFID devices may store environmental data (that may be detected by an associated sensor), logistical histories, state data, etc.
Often RFID products are configured in relatively uniform designs for use in large-scale applications, such as may be found in large retailing situations. These designs, once proven and implemented may take weeks or even months to produce. Such designs however, often will not function in small to mid level applications for which RFID products may be useful. However, due to the small unit volumes, often less than 50,000 units, many of the suppliers of RFID products are simply unwilling, largely because of cost, to undertake the design and development of specialized tags for these niche applications.
In addition, different RFID devices may have to perform to different performance requirements, and/or to perform in different operating environments. There is a need to provide RFID devices that are able to meet various requirements and to perform in various conditions. It will be appreciated that satisfying that need would be desirable.